What the Neocortex Does
Gary Forbis
GaryForbis at email.msn.com
Sat Aug 5 23:07:50 EST 2000
"Harry Erwin" <herwin at gmu.edu> wrote in message news:1eew5z2.15oy2at1guvygwN%herwin at gmu.edu...
> Kevin K. <KK at _._> wrote:
>
> > Gary Forbis wrote:
> > >
> > > "Kevin K." <KK at _._> wrote in message news:3989AC71.7969B1CA at _._...
> > > >
> > > >
> > > > Harry Erwin wrote:
> > > >
> > > > > You're missing my point. Symbols are signs. They belong to a countable
> > > > > set. Wind-tunnel models can vary continuously (or discontinuously). That
> > > > > matters--there are some applications (for example in hydraulic analysis)
> > > > > where symbolic modeling encounters an intractable problem, but analog
> > > > > modeling works fine.
> > > >
> > > > Intractability is a an issue relating to computational efficiency --
> > > > i.e. the time or space required to perform the calculation. It has no
> > > > bearing on Church's thesis. A Turing machine can be written to solve the
> > > > hydraulic problem to any desired degree of accuracy because the TM has
> > > > an infinite supply of time and space. It may take a while, but that's
> > > > okay, because Church's thesis concerns computability in principle, not
> > > > in practice.
> > >
> > > I hate "in principle" arguments applied to real objects.
> >
> > That's what this thread is about, in reverse. Mr. Erwin claimed that a
> > real object (the bat brain) had some bearing on a longstanding
> > mathematical principle (Church's thesis).
> >
> > BTW, do you hate it when "in principle" arguments like "the interior
> > angles of triangle total 180 degrees" are applied to real triangles? ;-)
I didn't know that was an "in principle" argument. Besides, while it applies
in Euclidian space it needn't apply everywhere.
> Well, I did spend a year learning to program a Turing machine when I was
> working on that PhD in algebraic topology. I'm probably one of the few
> people actually qualified to compare mathematical reasoning (what Turing
> was trying to reduce to syntax) to computational processes in wet
> networks.
Now, I'm going to be in real trouble.
Are there "computational processes in wet networks" or is it that the
processes in wet networks can be described computationally? Again,
does a rock perform computations by falling? What makes a process
a computational process?
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